Quality control of embankment compaction has an important influence on the durability and stability of the high embankment airport. Now, the unmanned compaction quality control mainly depends on the path tracking effect of the unmanned roller. The path tracking error of the roller increased obviously in the field test. The error from the perspective of the discontinuity of the planning path curvature was analyzed by a simulation model built based on the pure pursuit algorithm. Then the arc and elliptical arc were selected to simplify the planning path, and the results show that the optimized arc path made the tracking error reduced effectively. In order to further reduce the error, the inflection point of the straight line and the arc was smoothed by the method of rounding and cubic B-spline curve fitting, respectively. The simulation results show that the rounding process and the B-spline curve fitting have significant effects on improving the path tracking of the vehicle.

From the viewpoint of the effective use of materials and environmental conservation, the recycling of waste materials generated at construction sites has been increasingly required. Asphalt pavement materials that are left after pavement repair are among such waste materials. Thus, for the purpose of effectively using waste asphalt, the applicability of recycled asphalt as a civil engineering material was examined by conducting laboratory tests and the trial construction of embankments. It was found that waste asphalt could be used in embankments and in frost blankets, and could be used for improving unsuitable soil.

In this study the Distinct Element Method (DEM) with a size-dependent bond contact model was employed to investigate the fracture mechanism induced by TBM cutting in rock mass with a group of cross joints, where the effect of joint inclination angle under two cutters was analyzed. The center joint outcrop is fixed at a distance of 20 mm with the rock mass center. The DEM results show that the process of rock fragmentation can be divided into three stages: loading stage, unloading stage and residual jumping stage. The peak normal thrust decreases gradually with the decrease of joint angle α. During the process, the number of bond failure increases gradually with the increase of invasion depth. There are two distributions of bond failure in different joint angles. One is the bond failure concentrates between the cutter and the shallow joint. The other one is the bond failure crosses the shallow joint and reaches the next joint

With the continuous increase of high-embankment construction projects in China's airports, impact roller has become more and more widely used. And the construction technology with automatic driving, path planning and adaptive operation has become the development direction in high-embankment airport. Combined with advanced information technology such as Beidou positioning navigation system, the Internet and cloud computing, this paper proposes an algorithm for optimal path planning of impact roller to meet the need. The algorithm includes three aspects: working surface rasterization, full coverage path generation and optimal path planning. Based on the structure of the impact roller, the algorithm adopts the method of non-overlapping wheel tracks to plan the path which covers the entire working surface, and could get the optimal path by analyzing the compaction quality during the construction process. Through field test, it is proved that the proposed algorithm has certain feasibility and effectiveness in guiding impact roller to work. The impact roller can not only ensure the compaction quality, but also improve work efficiency by following the path generated by the algorithm.

The composition of inert waste landfill is important from the geotechnical and geoenvironmental point of view, as the concrete and rock wastes help in increasing the bearing capacity and the fibrous fractions can act as reinforcement to increase the volume of the inert waste landfill. In contrast, the presence of fibrous fractions may cause the storage of water inside the inert waste landfill and there are also some possibilities of presence of toxic and degradable matters in the inert waste materials. In this paper, the results from the field tests such as composition analysis, basic physical properties, angle of repose, CASPOL impact value test and in-situ direct shear test are discussed to evaluate the change in mechanical characteristics and basic physical parameters (in situ density etc.) of inert wastes. Change in the strength parameters are observed with respect to change in different components of the inert waste and age after reclamations. The results show that the density and impact value decrease for increase in fibrous content under 20%. For direct shear test, shear stress increases with increase in high fibrous content. In the laboratory column leaching test, the change in the leachate behavior is observed due to 2% and 10% fibrous content. The water storage and EC are found lower for the column with 10% fibrous content than that of 2% fibrous content. TOC is found higher for 2% fibrous content but the values are found to be within the standard limit.

Transparent soil surrogates permit nonintrusive three-dimensional deformational measurements in geotechnical model tests. Fused quartz saturated with a matched refractive index oil blend is an appropriate surrogate for natural sands. This paper carried out oedometer tests, consolidated drained (CD) triaxial tests and permeability tests on loose and dense oil-blend-saturated fused quartz. The geotechnical properties of compressibility, strength and permeability of the fused quartz were investigated experimentally and compared to those of natural sands and other transparent soil materials. An optimum transparency was obtained with a volume ratio of #15 white mineral oil and n-dodecane of 10:7.5 at room temperature. The dense fused quartz was less compressible with the coefficient of compressibility (α1-2) being 0.192 MPa-1. The intrinsic permeability ranged from 18.7 to 31.5 darcys and the differences from the natural sands were ignorable. The peak friction angle ranged between 40.9 and 47.3°, which was within the typical range of sands. The test results show that fused quartz serves as an applicable surrogate in scaled model tests such as tunnel face stability experiments.

An estimated volume of 14 million m3 of the removed soil and waste generated from decontamination projects in Fukushima Prefecture is being transported to the interim storage facility at present. Modification agents such as water-absorbing polymer are used to improve the treatability of the removed soil for efficient separation of foreign materials. It is expected that the modified removed soil can be reused as geomaterial to reduce the final disposal volume under the major premise of safety assurance. Thus, it is important to understand the mechanical properties of the modified removed soil and the influence of the modification agents. This study focused on the compressibility and the unconfined compressive strength of the modified removed soil. Compression tests using oedometer and unconfined compression tests were conducted on the removed soil modified with a water-absorbing polymer powder agent and the mix proportion by weight was 3% and 10%. Decomposed granite soil was used as a comparison. With addition of 10% polymer agent, the final settlement of the modified removed soil decreased by 20% and the unconfined compressive strength increased by 80% to 82 kN/m2. The results suggest that the mechanical performance of the modified removed soil might be improved with a certain amount of polymer agent addition.

The influence of particle size on the mechanical behavior of calcareous sand, which was obtained from the seabed in South China Sea, was studied. A series of triaxial compression tests were carried out on samples with different particle size distributions, which the maximum diameters of particles are 2 mm and 20 mm respectively. The results show that calcareous sand presents stress-strain soften behavior. The shear stress increase with particle size. With the increase of shear strain, the volumetric strain changes from contraction to dilatation. The dilatation tendency decrease with increasing particle size and effective confining pressure. Samples with coarse grains (≤20 mm) shows completely compression under high effective confining pressure (800 kPa). The peak state friction angle and critical state friction angle were also influenced by particle size. There is unique critical state line in p^'-q plane no matter particle size.